IGNITION COIL RELAY MODIFICATION

[dicky]

The guy in that video is making buzz coil, or trembler, ignitions.
These were used in Model T Fords, not modern Japanese motorcycles.
The modification discussed here is simply to provide the maximum voltage to the ignition coil by using an after market relay and a more direct electrical path.

[epsilon]

Hello everyone,
I hope you all be safe and healthy.

Coming back to this mod, i have done it and works like a charm. Been looking on videos about lithium batteries i came across
a dc to dc step up converter something like this https://www.ebay.com/sch/i.html?_nkw=Dc ... 0Converter.

In theory it might work take for example 10v from battery and give 14v or even 15v to the coils constanly.
What's your opinion about this?
Also this type of converter has a max load of 2A,3A,5A, does anyone know how many Amps our electical system works to be on the safe side
if i try to do this mode without destroy the wires or coils?

Thanks in advance

[dicky]

I would not increase the low voltage side of the coil any further than it was designed to work at (i.e. 12~14v)
The relay modification eliminates any unnecessary drop in voltage and gives a low resistance circuit to provide the most current to the coil.
The coil is simply a transformer hooked up 'backwards' so that instead of dropping a high voltage to a lower one, it increases a low voltage to a higher one.
The coil input, coming from the ignition unit, is just a short pulse but it needs a fair bit of current to make the transformer work correctly, hence the relay mod.
To get more spark you need more output voltage, but you don't do that by increasing the input voltage.
The windings on the output side of the coil are only rated to work at the specified input voltage. You risk overheating and burning out the coil if you increase the input.
In race engines they often use 'high performance' coils, but these are simply a transformer designed with a higher output voltage, they still operate on the same input voltage.

[epsilon]

Ok, i know how the coils work.

My first thought was to have a constant input voltage to the coils, cause with this mode it depends on the battery available
voltage a that time.A properly good battery will give 13,5v to 14v and that ok for this mod to work.

But after a while there is a possibility of a little drop in the voltage from the battery,that's why i had this idea to have
a constant voltage feed for the coils not overfeed them,let's say between 13,5v to 14v.

[dicky]

You already have a constant input voltage to the coil, it is connected to the battery +ve and the output of the regulator.
Other than starting or letting the revs drop to idle the voltage will be the output of the regulator.

[gurunik]

Decent idea, if you have issues, but having done it to a few bikes, you gain little on a road setup, other than add stuff. Race setup and high compression, it's a valid path. Coming from a worked off its tits cb7504k2, i am loving how i don't have to tune this trx every month.... for about same power, but way down were you can use it. no more thinking 3 gear changes ahead.... sweet

[gurunik]

Bear in mind the the coil is switched via the ground it sees through the ecu. A good feed is a good thing, but it has go somewhere, and that is up to the ecu, and it's ground. I would probably leave the switching side alone ( coil to box) and just make sure the grounds are all shiny. Increase potential current, and it's up to the box to take it, but it's only a volt(amp) or so, so little risk for nice gain.....

[reginald]

If anyone is still reading this topic I need help to identify where Cobba's... green wire is going to. I understand that of the 4 relay male fingers (?) 1 wire goes to ground; 1 wire goes to the starter relay; 1 wire goes to the coil(s)(to replace the red/white wires) and the fourth wire (Cobba's green wire) goes to???? (I'm guessing it replaces either the orange or grey feed from the CDI to the coils). Can someone clarify this for me please. Thank you
Reggie

[reginald]

Or...does Cobba's green wire replace the red/white feed from the CDI unit?
Reggie

[reginald]

It's o.k. I worked it out. There is a great schematic (coil relay mod) over on the (yamaha) fjowners.com website. Cheers
Reggie